1. Field of the Invention
The present invention relates to an electronic balance having at least one function which can be additionally switched on and which is secured against unauthorized switching on by a locking means arranged in the balance housing. The balance housing has an opening for inserting a member for the actuation of the locking means.
2. Description of the Related Art
Modern electronic balances may have a plurality of functions, wherein some of these functions serve for the adjustment of the balance, for example, for the calibration of the balance. It should be possible to make some of these functions, such as the calibration of the balance, inaccessible to unauthorized operating personnel, wherein these functions should be for legal reasons only accessible to authorized persons, such as an official of a bureau of weights and measures.
In some known electronic balances, the function which is usually locked, for example, the calibration function, is activated after opening the housing balance by changing the position in which a jumper is arranged on the balance print. This rearrangement of the jumper insure that the desired functions are locked because the housing is usually secured by a seal or another means which indicates that the housing has been opened. In balances which include a draft protection device, the structures which form the draft protection device must be disassembled for carrying out a calibration and subsequently the balance housing whose upper portion is screwed to the bottom must be opened. After the calibration has been carried out, the previously disassembled parts must again be joined together and, if it is found that the calibration was not carried out with the desired result, the balance housing and any draft protection device placed on the balance housing must again be disassembled. This is cumbersome and each opening of the balance may lead to problems which can only be eliminated by trained maintenance personnel of the balance manufacturer.
In other known balances, the balance housing has an opening and the balance includes a switch arranged behind the opening. For actuating the switch, a tool, for example, a screwdriver, must be inserted through the opening into the interior of the balance. During this procedure, the inserted screwdriver may damage parts of the balance, particularly electronic components on the print. The actuation of the switch by means of the screwdriver requires precise knowledge of the balance, i.e., location of the switch behind the opening, on the one hand, and significant dexterity in finding the switch without contacting elements of the balance next to or behind the switch, on the other hand.